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Enhanced modeling of microlensing variations in light curves of strongly lensed quasars improves measurements of cosmological time delays, the Hubble Constant, and quasar structure. Traditional methods for modeling extra-galactic…

Instrumentation and Methods for Astrophysics · Physics 2025-01-03 Somayeh Khakpash , Federica Bianco , Georgios Vernardos , Gregory Dobler , Charles Keeton

Automated Algorithm Selection (AAS) is a popular meta-algorithmic approach and has demonstrated to work well for single-objective optimisation in combination with exploratory landscape features (ELA), i.e., (numerical) descriptive features…

Neural and Evolutionary Computing · Computer Science 2026-02-03 Oliver Preuß , Jeroen Rook , Jakob Bossek , Heike Trautmann

We develop a new statistical method to reanalyse angular correlations between background QSOs and foreground galaxies that are supposed to be a consequence of dark matter inhomogeneities acting as weak gravitational lenses. The method is…

Astrophysics · Physics 2007-05-23 Armin Bartsch , Peter Schneider , Matthias Bartelmann

Correlating BASS DR3 catalogue with ALLWISE database, the data from optical and infrared information are obtained. The quasars from SDSS are taken as training and test samples while those from LAMOST are considered as external test sample.…

Instrumentation and Methods for Astrophysics · Physics 2021-11-17 Changhua Li , Yanxia Zhang , Chenzhou Cui , Dongwei Fan , Yongheng Zhao , Xue-Bing Wu , Jing-Yi Zhang , Jun Han , Yunfei Xu , Yihan Tao , Shanshan Li , Boliang He

We are entering an era of unprecedented quantities of data from current and planned survey telescopes. To maximise the potential of such surveys, automated data analysis techniques are required. Here we implement a new methodology for…

We present a novel method for the optimal selection of quasars using time-series observations in a single photometric bandpass. Utilizing the damped random walk model of Kelly et al. (2009), we parameterize the ensemble quasar structure…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Nathaniel R. Butler , Joshua S. Bloom

Spin-crossover (SCO) metal-organic frameworks (MOFs) hold great promise for sensing, spintronics, and gas-related applications, however, only a small number of SCO-active examples are known among the thousands of MOFs already synthesized.…

Materials Science · Physics 2026-03-05 Ashna Jose , Emilie Devijver , Martin Uhrin , Noel Jakse , Roberta Poloni

Our group has developed a technique that makes use of the observed non-linear relation between the ultraviolet and the X-ray luminosity in quasars to provide an independent measurement of their distances, thus turning quasars into…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-05 Elisabeta Lusso

Maximum likelihood estimation of large Markov-switching vector autoregressions (MS-VARs) can be challenging or infeasible due to parameter proliferation. To accommodate situations where dimensionality may be of comparable order to or…

Econometrics · Economics 2021-07-28 Kenwin Maung

The faint-end slope of the quasar luminosity function at z~6 and its implication on the role of quasars in reionizing the intergalactic medium at early times has been an outstanding problem for some time. The identification of faint…

Obtaining accurate photometric redshift estimations is an important aspect of cosmology, remaining a prerequisite of many analyses. In creating novel methods to produce redshift estimations, there has been a shift towards using machine…

Instrumentation and Methods for Astrophysics · Physics 2021-07-07 Ben Henghes , Connor Pettitt , Jeyan Thiyagalingam , Tony Hey , Ofer Lahav

In the second paper of this series we extend our Bayesian reanalysis of the evidence for a cosmic variation of the fine structure constant to the semi-parametric modelling regime. By adopting a mixture of Dirichlet processes prior for the…

Instrumentation and Methods for Astrophysics · Physics 2013-09-12 Ewan Cameron , Tony Pettitt

We consider the problem of identifying significant predictors in large data bases, where the response variable depends on the linear combination of explanatory variables through an unknown link function, corrupted with the noise from the…

Methodology · Statistics 2019-11-19 Wojciech Rejchel , Malgorzata Bogdan

The Hubble tension, revealed by a $\sim 5\sigma$ discrepancy between measurements of the Hubble-Lemaitre constant from early- and local-Universe observations, is one of the most significant problems in modern cosmology. In order to better…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-12 Zizhao He , Nan Li , Xiaoyue Cao , Rui Li , Hu Zou , Simon Dye

We obtained medium-resolution spectra of 336 quasar candidates in the COSMOS HST/Treasury field using the MMT 6.5-meter telescope and the Hectospec multi-object spectrograph. Candidates were drawn from the Sloan Digital Sky Survey (SDSS)…

Astrophysics · Physics 2009-11-11 M. K. M. Prescott , C. D. Impey , R. J. Cool , N. Z. Scoville

Improving the retrieval relevance on noisy datasets is an emerging need for the curation of a large-scale clean dataset in the medical domain. While existing methods can be applied for class-wise retrieval (aka. inter-class), they cannot…

Computer Vision and Pattern Recognition · Computer Science 2022-04-08 Xiaoyuan Guo , Jiali Duan , Saptarshi Purkayastha , Hari Trivedi , Judy Wawira Gichoya , Imon Banerjee

The Common Objects in Context (COCO) dataset has been instrumental in benchmarking object detectors over the past decade. Like every dataset, COCO contains subtle errors and imperfections stemming from its annotation procedure. With the…

Computer Vision and Pattern Recognition · Computer Science 2024-03-28 Shweta Singh , Aayan Yadav , Jitesh Jain , Humphrey Shi , Justin Johnson , Karan Desai

This paper explores the application of machine learning methods for classifying astronomical sources using photometric data, including normal and emission line galaxies (ELGs; starforming, starburst, AGN, broad line), quasars, and stars. We…

The classification of individual traffic participants is a complex task, especially for challenging scenarios with multiple road users or under bad weather conditions. Radar sensors provide an - with respect to well established camera…

Machine Learning · Computer Science 2019-05-28 Nicolas Scheiner , Nils Appenrodt , Jürgen Dickmann , Bernhard Sick

The compressed sensing (CS) model can represent the signal recovery process of a large number of radar systems. The detection problem of such radar systems has been studied in many pieces of literature through the technology of debiased…

Signal Processing · Electrical Eng. & Systems 2023-07-03 Siqi Na , Yoshiyuki Kabashima , Takashi Takahashi , Tianyao Huang , Yimin Liu , Xiqin Wang